A screw compressor for a utility vehicle has at least one female screw, at least one male screw that meshes with the female screw, and at least one screw compressor drive which drives the female screw.

A positive displacement device that converts energy, namely positive displacement compressors that rotate in a single rotational direction to displace working fluid contained in operating chambers. The device described herein is particularity advantageous for the ability to achieve high compression ratios in combination with high discharge pressure and high volumetric throughput in a single stage.

This screw compressor is provided with a screw rotor, a casing accommodating the screw rotor, and a liquid feed mechanism for feeding a liquid into an operating chamber enclosed by the casing, wherein the pitch of the screw rotor changes in the axial direction from a suction end surface toward a discharge end surface.

A structure comprising a rotor body, the rotor body including a rotor shaft arranged on one end face of the rotor body, a sub-shaft cavity opened in the rotor shaft, and locating keyways symmetrically opened on both sides inside the sub-shaft cavity; a sub-shaft arranged on the other end face of the rotor body, and sub-shaft locating keyways symmetrically opened on both sides of the sub-shaft.

Provided is a rotor structure of a screw compressor and an inverter screw compressor with the same. The rotor structure includes: a female rotor including a female rotor body, wherein the female rotor body includes a plurality of female teeth, and a tooth profile is formed between tooth crests of two adjacent female teeth of the female rotor body, and the tooth profile is formed by sequentially connecting an arc segment a.sub.1b an envelope bc, an arc segment cd, an arc segment de, an arc segment ea.sub.2, an arc segment a.sub.2a.sub.3 from front to rear along a counterclockwise direction, wherein centers of the arc segment cd and the arc segment de are respectively located on both sides of the tooth profile.

The present invention concerns a dry vacuum pump comprising: a drive device (1) comprising a drive shaft (3) at one end of which is fixed at least one drive wheel (4) provided to set in motion at least one belt (5); at least two parallel rotors (7, 8) each having a shaft (9, 10) provided with a rotor element (11, 12), this shaft (9, 10) being able to be driven in rotation by the belt (5) and being equipped at one of its axial ends with a toothed wheel (13, 14), this pump having the special features that: the drive wheel (4) and the belt (5) are smooth; each shaft (9, 10) of the rotor (7, 8) comprises at least one smooth section (16, 17) arranged to co-operate with the belt (5), and the toothed wheels (13, 14) of the shafts (9, 10) of the rotor (7, 8) are dimensioned and arranged to mesh with one another.

A compressor design includes a male rotor (10) having one or more helical lobes (12) and a female rotor (14) having one or more helical grooves (16). The male rotor is mounted on a first shaft and the female rotor is mounted on a second shaft. The male rotor is positioned in a first section of a chamber and the female rotor is positioned in a second section of the chamber. Fluid enters the chamber at an inlet, and when the rotors are driven, the lobes of the male rotor fit into the grooves of the female rotor, causing compression and movement of the fluid towards an outlet or discharge end where the compressed fluid is discharged. The configuration of the lobe and groove helix, the lobe and groove profile, and the outer diameter of the rotors can be varied in different combinations to form different rotors.

The invention relates to a screw pump having two screws, in which screw pump each screw has a first thread and a second thread. The threads extend in each case from a suction side to a delivery side. The threads are in engagement with one another, with the result that the threads are divided into a plurality of working chambers, the volume of which decreases from the suction side to the delivery side. According to the invention, the threads have two thread turns. Moreover, the invention relates to a screw for a pump of this type. On account of the uniform distribution of mass of the two-turn threads, the pump can be operated at a high rotational speed, with the result that the throughput of the pump is increased.

A Roots-type blower may include first and second meshed, lobed rotors disposed in first and second chambers of a housing. Each lobe may have first and second axially facing end surfaces defining a twist angle that may be a function, at least partially, of the number of lobes on each rotor. A blower housing may include a bearing plate that may include one or more internal pressure relief ports. A pressure relief port may be configured to relieve fluid pressure from a trapping area that may form between first and second meshed rotors.

A multistage Roots pump comprise a plurality of pump chambers in a pump housing. They constitute respective pump stages, wherein each pump stage comprises two two-toothed rotary pistons. The pump stages are separated from each other by partition walls. In the partition walls essentially radially extending connecting ducts are arranged. The connecting ducts are connected with an inflow chamber whose inflow opening has a larger cross-section than the connecting ducts.